Tumour angiogenesis and prognosis

The role of long non-coding RNAs in angiogenesis and anti-angiogenic therapy resistance in cancer

It is well known that long non-coding RNAs (lncRNAs) play an important role in the regulation of tumor genesis and development. They can modulate gene expression of transcriptional regulation, epigenetic regulation of chromatin modification, and post-transcriptional regulation, thus influencing the biological behavior of tumors, such as cell proliferation, apoptosis, cell cycle, invasion, and migration. Tumor angiogenesis not only provides nutrients and helps excrete metabolites, but it also opens a pathway for tumor metastasis. Anti-angiogenic therapy has become one of the effective treatment methods for tumor. But its drug resistance leads to the limitation of clinical application. Recent studies have shown that lncRNAs are closely related to tumor angiogenesis and anti-angiogenic therapy resistance, which provides a new direction for tumor research. lncRNAs are expected to be new targets for tumor therapy. For the first time to our knowledge, this paper reviews advancement of lncRNAs in tumor angiogenesis and anti-angiogenic therapy resistance and further discusses their potential clinical application.

Prognostic value of microvessel density in esophageal squamous cell carcinoma-a systematic review and meta-analysis

OBJECTIVE

Angiogenesis produced by tumor microenvironment is play an important role in development of esophageal squamous cell carcinoma (ESCC). As a quantitative index of angiogenesis, literature has emerged contradictory results about the prognostic role of microvessel density (MVD) in ESCC. The aim of the study was to explore the impact of the correlation between MVD and the prognosis of ESCC based the published evidence.

METHODS

Pubmed and Web of science database were screened for the relationship of MVD with prognostic feature in ESCC up to March, 2021. 11 relevant articles were used for meta-analysis. The following data were extracted from the literature: author, year, country, the patients number of high/low MVD, tumor-node-metastasis (TNM) classification, clinical stage, lymphoid infiltrates, vessel invasion, invasive depth, differential degree and survival rate. The hazard ratio (HR) and odds ratios (OR) with 95% CI were used to assess the associations between MVD and overall survival (OS). Chi-squared test and I² statistics were completed to evaluate the heterogeneity in our study. A random-effects model was used when significant heterogeneity existed (I²>50% and p < 0.05). Egger test was used to calculate the publication bias. Subgroup analysis was stratified by antibody, region, sample capacity to explore the source of heterogeneity.

RESULTS

11 studies with 1055 patients were analyzed. Our results suggested that high MVD is an important factor to advanced TNM classification and clinical stage, and the high MVD is positive correlation with the lymph node invasion and vascular invasion(p < 0.05) in ESCC, but irrelevant to poor differential and invasive depth(p > 0.05). The result also indicated that low MVD is a benefit factor to prolong the survival rate (p < 0.05). And the source of the heterogeneity maybe is that the antibody used to detect the MVD was not consistent, patient number was not large enough and the count method on MVD.

CONCLUSION

Across multiple studies, high MVD is correlated with clinicopathological criteria of poor prognosis and survival in ESCC. MVD could be the quantitative index to reactive angiogenesis and may play a pivotal role in ESCC development and progression. MVD may represent a valuable addition to current pathologic analysis and help to guide prognosis and treatment.

Microvessel Density and Impact of Angiogenesis on Survival of Resected Pancreatic Cancer Patients: A Systematic Review and Meta-analysis

OBJECTIVES

Angiogenesis plays a major role in tumor progression and metastasis; however, its role in pancreatic cancer (PC) remains unclear. The aim of the study was to explore the cumulative evidence concerning the impact of microvessel density (MVD), an estimator of angiogenesis, on resected PC patients.

METHODS

A systematic review of literature and a meta-analysis of relevant reports were performed. Overall survival and disease-free survival were scrutinized.

RESULTS

One thousand five hundred patients were analyzed. Overall survival (hazard ratio, 2.0; 95% confidence interval, 1.57-2.54; P < 0.001) and disease-free survival (hazard ratio, 1.99; 95% confidence interval, 1.24-3.2; P = 0.004) were in favor of the low-MVD group. Use of CD105 antibody and of a computerized image analysis system was found to significantly reduce the heterogeneity. Disease staging, tumor location, and grading showed significant effect on survival.

CONCLUSIONS

High-MVD expression was strongly associated with poorer survival and recurrence among resected PC patients, demonstrating a negative prognostic value. Use of CD105 antibody and of a computerized image analysis system is recommended in future studies because they reduce heterogeneity of results. The potential role of MVD as a marker to select PC patients who would benefit from antiangiogenetic treatment should be further explored in clinical trials.

Contrast-Enhanced Ultrasound Differentiation Between Low- and High- Grade Bladder Urothelial Carcinoma and Correlation With Tumor Microvessel Density

OBJECTIVES

Time-intensity curves (TICs) of contrast-enhanced ultrasound (CEUS) were analyzed retrospectively to differentiate between low-grade and high-grade bladder urothelial carcinoma, and to investigate correlation with tumor microvessel density (MVD).

METHODS

The data of 105 patients with pathologically confirmed bladder urothelial carcinoma (55 low-grade and 50 high-grade) were reviewed. Lesions were examined before surgery using conventional ultrasound and CEUS with TIC analysis. The TIC parameters time from peak to one-half the signal intensity (TPH) and the corresponding descending slope (DS) of the low-grade and high-grade groups were compared, and receiver operating characteristic curves constructed. The MVDs of the resectioned tissue specimens were quantified via immunohistochemistry for CD34.

RESULTS

Based on conventional ultrasound, the low-grade and high-grade groups were similar in tumor shape, number, topography, internal echo, height, width, and vascularity. The TPH of the high-grade group was significantly longer than that of the low-grade group, and the DS was lower. The cutoff points of TPH and DS for differentiating low-grade and high-grade bladder urothelial carcinoma were 48.06 seconds and 0.15 dB/seconds, respectively (area under the receiver operating characteristic curve = 0.79 for both). The mean MVDs per high-power field of the low-grade and high-grade groups were 41.39 16.65 and 51.03 20.16, respectively (P = .009). The TPH correlated linearly with MVD (P < .01), as did the DS (P < .01).

CONCLUSIONS

Contrast-enhanced ultrasound can be used to differentiate low from high-grade bladder urothelial carcinoma. The TIC parameters of CEUS reflect the MVD of bladder urothelial tumors and may be helpful for evaluating tumor angiogenesis, with implications for clinical diagnosis, treatment, and prognosis.

Microvessel Density as a Surrogate Prognostic Marker in Patients with Multiple Myeloma: A Meta-Analysis

BACKGROUND/AIMS

Bone marrow (BM) angiogenesis is considered a hallmark of multiple myeloma (MM) development and progression, and can be quantified with the use of microvessel density (MVD). The purpose of this study is to provide a review and a meta-analysis of the current literature regarding the prognostic value of MVD in the overall survival (OS) of MM patients.

METHODS

MEDLINE was screened for studies evaluating the OS of MM patients with regard to their MVD count in BM trephine. The pooled hazard ratio (HR) and its associated 95% confidence interval (CI) among MM patients with a high and low MVD count was the primary end point. Secondary outcomes included odds ratios (OR) for 12-, 36-, and 60-month survival.

RESULTS

Ten eligible trials were identified for the analysis of the primary end point and 9 for the secondary end points. Pooled HR for OS was 1.85 (95% CI: 1.25-2.73, p = 0.002). The pooled OR of survival were 1.59 (95% CI: 1.02-2.46, p = 0.04) at 12 months, 2.90 (95% CI: 1.68-5.03, p = 0.0001) at 36 months, and 3.42 (95% CI: 2.41-4.85, p < 0.00001) at 60 months, in favor of the low MVD group.

CONCLUSION

This meta-analysis provides persuasive evidence that MVD has significant impact on the clinical outcome of MM patients.

Expression of Proliferating Cell Nuclear Antigen (PCNA) in Multiple Myeloma: Its Relationship to Bone Marrow Microvessel Density and other Factors of Disease Activity

The expression of the proliferating cell nuclear antigen (PCNA) was studied in plasma cells in bone marrow biopsies from patients with multiple myeloma (MM) using a double immunostaining method. In the same samples, microvessel density (MVD), after staining with anti-CD34 antibodies, was determined before and after chemotherapy. The correlation of PCNA expression and MVD with other myeloma parameters (clinical stage, bone marrow plasma cell infiltration and serum interleukin –6 (IL-6)) was also investigated.

The study population included 51 newly diagnosed MM patients, 12 patients in plateau phase after treatment and 15 normal controls. Pretreatment mean ± SE values of PCNA, MVD, plasma cell infiltration and serum IL-6 were significantly higher than post treatment values and controls. Pretreatment PCNA expression correlated significantly with bone marrow MVD (p<0.05) plasma cell infiltration (p<0.01) and IL-6 (p<0.01).

These findings show that the proliferative activity of plasma cells is related to the angiogenic activity in the bone marrow of multiple myeloma patients. Both PCNA and MVD correlate with markers of disease activity thus may provide additional information when included in the initial evaluation of myeloma bone marrow biopsies.

The Use of Breast Magnetic Resonance Imaging Parameters to Identify Possible Signaling Pathways of a Serum Biomarker, HE4

OBJECTIVES

This study aimed to investigate the relationship between breast magnetic resonance imaging (MRI) parameters; clinical features such as age, tumor diameter, N, T, and TNM stages; and serum human epididymis protein 4 (HE4) levels in patients with breast carcinoma and use this as a means of estimating possible signaling pathways of the biomarker, HE4.

METHODS

Thirty-seven patients with breast cancer were evaluated by breast MRI and serum HE4 levels before therapy. Correlations between parameters including age, tumor diameter T and N, dynamic curve type, enhancement ratio (ER), slope washin (S-WI), time to peak (TTP), slope washout (S-WO), and the serum level of HE4 were investigated statistically. Human epididymis protein 4 levels of early and advanced stage of disease were also compared statistically.

RESULTS

Breast MRI parameters showed correlation to serum HE4 levels and correlations were statistically significant. Of these MRI parameters, S-WI had higher correlation coefficient than the others. Human epididymis protein 4 levels were not statistically different in early and advanced stage of disease.

CONCLUSIONS

High correlation with MRI parameters related to neoangiogenesis may indicate signaling pathway of HE4.

Assessing Tumor Angiogenesis in Histological Samples

Tumor neovascularization acquires their vessels through a number of processes including angiogenesis, vasculogenesis, vascular remodeling, intussusception, and possibly vascular mimicry in certain tumors. The end result of the tumor vasculature has been quantified by counting the number of immunohistochemically identified microvessels in areas of maximal vascularity, so-called hot spot. Other techniques have been developed such as Chalkley counting and the use of image analysis systems that are robust and reproducible as well as being more objective. Many of the molecular pathways that govern tumor neovascularization have been identified and many reagents are now available to study these tissue sections. These include angiogenic growth factors and their receptors and cell adhesion molecules, proteases, and markers of activated, proliferating, cytokine-stimulated, or angiogenic vessels, such as CD105. It is also possible to differentiate quiescent from active vessels. Other reagents that can identify proteins involved in microenvironmental influences such as hypoxia have also been generated. Although the histological assessment of tumor vascularity is used mostly in the research context, it may also have clinical applications if appropriate methodology and trained observers perform the studies.

Correlation between selected angiogenic markers and prognosis in pediatric adrenocortical tumors: Angiogenic markers and prognosis in pediatric ACTs

BACKGROUND/PURPOSE

Pediatric adrenocortical tumor (ACT) remains a challenging disease. Tumor weight and disease stage are still the most used indicators to prognosis and guidance of clinical decisions. Histology has not added meaningful data for risk stratification and management. ACT is metabolically active, highly vascularized, locally invasive and has the propensity to produce distant metastasis. Our objective was to correlate the expression of vascular endothelial growth factor (VEGF) and intratumoral microvessel density (MVD) with clinical and prognostic aspects in pediatric ACT.

PROCEDURE

In 27 tumors, immunohistochemical expression of VEGF, CD105 (endoglin) and CD34 was analyzed. MVD was determined by CD34 and CD105 antibodies. MVD and VEGF expression was correlated with clinical characteristics and outcome. Normal pediatric glands were used as controls.

RESULTS

Endoglin MVD was significantly higher and CD34 MVD was significantly lower in ACT than control. The VEGF expression did not differ between groups. Cytoplasmic staining for endoglin was correlated with hypertension in ACT. Endoglin MVD greater than 1 mv/field, CD34 MVD less than 32 mv/field and VEGF expression levels above 4.8% were associated with clinical and biological indicators of poor prognosis.

CONCLUSIONS

Endoglin and CD34 MVD values are potential histological markers to refine the histologic classification of pediatric ACT.

Knockdown of metadherin inhibits angiogenesis in breast cancer

Angiogenesis plays an important role in cancer growth, invasion and metastasis. It has been confirmed that metadherin (MTDH) is associated with angiogenesis. However, the detailed mechanism of MTDH on angiogenesis has not yet been reported. In this study, we demonstrate the anti-angiogenic function of MTDH in breast cancer. With RNA interference strategies, we found that knockdown of MTDH inhibits cellular angiogenesis both in vitro and ex vivo. Furthermore, we revealed that ERK1/2 pathway is involved in the anti-angiogenic function of MTDH, and the function can be partially reversed via upregulation of microRNA-21 (miR-21). In conclusion, knockdown of MTDH can inhibit angiogenesis in breast cancer. These results show that MTDH is a viable therapeutic target for anti-angiogenesis in breast cancer.

Diffuse optical tomography of breast carcinoma: can tumor total hemoglobin concentration be considered as a new promising prognostic parameter of breast carcinoma?

RATIONALE AND OBJECTIVES

Diffuse optical tomography (DOT) is an emerging functional modality, which can reflect tumor metabolic activity and angiogenesis. The purpose of this exploratory study was to correlate the total hemoglobin concentration (THC) measured by noninvasive DOT with prognostic factors in breast carcinomas.

MATERIALS AND METHODS

We prospectively imaged 251 breast carcinomas in 229 consecutive women (mean age, 51.18 ± 12.32 years) using DOT from 2007 to 2010. Tumor angiogenesis and metabolic activity were assessed based on quantitatively measured THC. The THC was correlated with prognostic factors, including tumor size, histopathologic classification, histologic grade, estrogen receptor (ER), progesterone receptor (PR), c-erbB-2, and p53.

RESULTS

In univariate analysis, THC was significantly correlated with the following prognostic factors: tumor size (P < .001), histologic grade (P < .001), ER (P < .05), PR (P < .001), and c-erbB-2 (P < .05). THC was not associated with histopathologic classification (P = .170) or p53 (P = .463). On the basis of a stepwise multiple regression analysis, THC of invasive ductal carcinoma was significantly correlated with tumor size (P < .001), histologic grade (P < .001), and PR (P < .05).

CONCLUSIONS

THC was associated with prognostic factors of breast carcinoma. THC may be considered as a new prognostic parameter of breast carcinoma and a prediction of tumor behavior and biological activity.

Additional value of dual-energy CT to differentiate between benign and malignant mediastinal tumors: an initial experience

OBJECTIVES

To investigate the feasibility of dual-energy computed tomography (DECT) in differentiating malignant from benign mediastinal tumors.

MATERIALS AND METHODS

We prospectively enrolled 25 patients (14 males; mean age: 56.7 years) who had suspected mediastinal tumors on chest radiography or non-contrast chest computed tomography (CT). All patients underwent a two-phase DECT using gemstone spectral imaging (GSI) mode (GE HD750). For the quantitative analysis, two investigators measured the following parameters of the tumors in the early and the delayed phases: CT attenuation value in Hounsfield units (HU) and iodine concentration (mg/ml). Pathological results were used for a final diagnosis. Statistical analyses were performed using the Fisher's exact test and the Mann-Whitney t-test.

RESULTS

10 patients (40%) had benign pathology, while 15 (60%) had malignant pathology. The iodine concentration measurements were significantly different between benign and malignant tumors both in the early phase (1.38 mg/ml vs. 2.41 mg/ml, p=0.001) and in the delayed phase (1.52 mg/ml vs. 2.84 mg/ml, p=0.001), while mean attenuation values were not significantly different in both phases (57.8 HU vs. 69.1 HU, p=0.067 and 67.4 HU vs. 78.4 HU, p=0.086, respectively).

CONCLUSIONS

Dual-energy CT using a quantitative analytic methodology can be used to differentiate between benign and malignant mediastinal tumors.

Prognostic vascular imaging biomarkers in high-grade gliomas: tumor permeability as an adjunct to blood volume estimates

RATIONALE AND OBJECTIVES

Despite recent advances in the treatment of high-grade gliomas, overall survival (OS) remains poor, which underlines the importance of searching for and determining prognostic imaging biomarkers. The purpose of our retrospective study was to correlate patient survival with relative cerebral blood volume (rCBV) and permeability surface area-product (PS) measured using perfusion computed tomography (PCT) in patients with high-grade gliomas.

METHODS

This study was composed of 54 patients with high-grade gliomas (World Health Organization [WHO] grade III, n = 14; WHO grade IV, n = 40) who underwent pretreatment PCT. Kaplan-Meier survival estimates were computed to describe OS for patients with high-versus-low PCT parameters, as well as grade III and IV gliomas.

RESULTS

Differences in OS between high and low rCBV, PS, and rCBV + PS were significant (P < .001) for all high-grade gliomas. After adjustment for WHO grade, rCBV (P = .041) and rCBV + PS (P = .013) estimates remained significant, whereas PS estimates were not (P = .214). PS estimates showed a statistically significant difference for OS in the grade III glioma group (P = .011), whereas for grade IV gliomas, rCBV estimates were statistically significant (P = .019). rCBV + PS was statistically significant for OS in both grade III (P = .001) and grade IV (P = .004) glioma groups.

CONCLUSIONS

Blood volume and permeability estimates measured using PCT can help predict survival in patients with high-grade gliomas. Patients with high PCT parameters showed worse OS compared to the patients with low PCT. Both rCBV and rCBV + PS remained statistically significant even after adjustment for WHO grade, suggesting these may be better predictors of OS than histological grade.

Relationships between Lymph Node Metastasis and Expression of CD31, D2-40, and Vascular Endothelial Growth Factors A and C in Papillary Thyroid Cancer

OBJECTIVES

To investigate the relationships between lymph node metastasis (LNM) and expression of CD31, D2-40 and vascular endothelial growth factors (VEGF)-A and -C in patients with papillary thyroid cancer (PTC).

METHODS

Paraffin-embedded thyroid tissues of 72 patients were evaluated, which included 25 patients with thyroid nodular hyperplasia (TNH), 24 PTC patients without LNM, and 23 PTC patients with LNM. Three pathologists, who were blinded to the patient's clinical information, assessed the immunohistochemical staining results. The amount of expression was scored as high (>25% of cells stained) or low (0-25%).

RESULTS

A higher level of VEGF-A expression was observed in the PTC groups regardless of LNM when compared to the group with TNH (91.3%, 79.2%, 4.0%, respectively). VEGF-C expression in the PTC with LNM group was significantly higher than the other two groups (P<0.05). No difference in microvessel density (MVD) scores was observed using CD31 among the three groups. The lymphatic vessel density (LVD) score using D2-40 was significantly higher in patients having PTC with LNM than the other groups (P<0.05).

CONCLUSION

VEGF-C and D2-40 were more highly expressed in patients having PTC with LNM than in patients having PTC without LNM or in those having TNH. Analysis of VEGF-C level and LVD using D2-40 may be helpful in the diagnosis of PTC and the evaluation of LNM potential in patients with PTC.

Correlation of expression of hypoxia-related proteins with prognosis in oral squamous cell carcinoma patients

INTRODUCTION

Hypoxia plays a major role in tumor progression, therapy resistance and for prognosis of oral squamous cell carcinoma (OSCC). The crucial step as a response to hypoxia is the activation and stabilization of the alpha subunit of hypoxia inducible factor 1 (HIF-1α). HIF-1: HIF-1 regulates the expression of different genes to adapt the tumor cells to reduced oxygenation. The HIF-1 system is intrinsic regulated by von Hippel-Lindau protein (pVHL). Main downstream proteins are the glucose transporter 1 (GLUT-1), carbonic anhydrase IX (CAIX), and vascular endothelial growth factor (VEGF). For therapeutical stratification in OSCC, it is important to understand the mechanism caused by hypoxic stress and to comprehend the resulting adaptive process in cancer cells. Therefore, an overview of HIF-1α-depending protein expression, focussed on the expression of GLUT-1, CAIX, and VEGF and their prognostic significance in OSCC is given.

CONCLUSION

Several unique roles of hypoxic pathway in the context of tumor progression are described in this review. As a consequence, a marker panel is proposed to allow a more individualized prognosis in OSCC patients. This marker panel should include beside HIF-1α, pVHL, and GLUT-1.

Microvessel density is high in clear-cell renal cell carcinomas of Ukrainian patients exposed to chronic persistent low-dose ionizing radiation after the Chernobyl accident

During the 25-year period subsequent to the Chernobyl accident, the morbidity of malignant renal tumors in Ukraine has increased from 4.7 to 10.7 per 100,000 of the total population. Recent studies of our group have shown that increases in morbidity, aggressiveness, and proliferative activity of renal cell carcinomas (RCCs), especially clear-cell renal cell carcinoma (CCRCC), in Ukrainian patients continuously inhabiting the radio-contaminated areas could be explained by specific molecular changes influenced by the so-called "chronic persistent low-dose ionizing radiation" (CPLDIR) exposure. This study aimed to examine the role of angiogenesis in CCRCC carcinogenesis associated with CPLDIR in patients living more than 20 years in cesium 137 ((137)Cs) contaminated areas after the Chernobyl accident in Ukraine. Paraffin-embedded specimens of 106 CCRCs were studied: Control cases were 18 tumors from Spanish patients (group 1), 25 tumors from Ukrainian patients from so-called clean areas without known radio-contamination (group 2), and 63 tumors from Ukrainian patients from radio-contaminated areas (group 3). For intratumoral microvessel density (MVD) determination, anti-CD31 antibody was used. A computerized image analysis program was used to quantitatively calculate the vascular density. Seventy-three percent of group 3 and 72 % of group 2 CCRCCs displayed the highest MVD. A striking increase in MVD was seen in group 3 CCRCCs, in comparison with groups 1 and 2 (p < 0.001). The majority of the hot spot vessels in group 3 was poorly differentiated. Moreover, MVD values for total vessels as well as for capillaries and tumor grade were strongly correlated. When we compared only tumor-node-metastasis tumor stages I and II, the differences remained statistically significant (p < 0.1). The ratio of the average total vessels and capillaries in the Ukrainian groups combined was 1.65:1 in comparison to the Spanish group. Our results provide evidence that CPLDIR exposure increases MVD (particularly capillary) in CCRCCs and is associated with a higher histological grade.

Xenon-inhalation computed tomography for noninvasive quantitative measurement of tissue blood flow in pancreatic tumor

BACKGROUND AND AIMS

The purpose of this prospective study was to demonstrate the ability to measure pancreatic tumor tissue blood flow (TBF) with a noninvasive method using xenon inhalation computed tomography (xenon-CT) and to correlate TBF with histological features, particularly microvascular density (MVD).

METHODS

TBFs of pancreatic tumors in 14 consecutive patients were measured by means of xenon-CT at diagnosis and following therapy. Serial abdominal CT scans were obtained before and after inhalation of nonradioactive xenon gas. TBF was calculated using the Fick principle. Furthermore, intratumoral microvessels were stained with anti-CD34 monoclonal antibodies before being quantified by light microscopy (×200). We evaluated MVD based on CD34 expression and correlated it with TBF.

RESULTS

The quantitative TBF of pancreatic tumors measured by xenon CT ranged from 22.3 to 111.4 ml/min/100 g (mean ± SD, 59.6 ± 43.9 ml/min/100 g). High correlation (r = 0.885, P < 0.001) was observed between TBF and intratumoral MVD.

CONCLUSION

Xenon-CT is feasible in patients with pancreatic tumors and is able to accurately estimate MVD noninvasively.

Perfusion parameters analysis of the vertebral bone marrow in patients with Ph¹⁻ chronic myeloproliferative neoplasms (Ph(neg) MPN): a dynamic contrast-enhanced MRI (DCE-MRI) study

PURPOSE

To evaluate perfusion parameters of the vertebral bone marrow in patients with Philadelphia negative chronic myeloproliferative neoplasms (Ph(neg) MPN) using dynamic contrast-enhanced MRI (DCE-MRI).

MATERIALS AND METHODS

The study enrolled 24 patients with Ph(neg) MPN: 12 patients with myelofibrosis (Group A), 6 with essential thrombocythemia (ET), and 6 with polycythemia vera (PV) (Group B) who underwent DCE-MRI of the lumbosacral spine. Twelve normal individuals served as control group (Group C). Wash-in (WIN), wash-out (WOUT), maximum contrast-enhancement (CE  max), time-to-peak (TTPK), time-to-maximum slope (TMSP), and the WIN/TMSP ratio (WTSP) were calculated.

RESULTS

WIN, CE(max) , and WTSP parameters were higher in Group A than in Group C (P < 0.05). These parameters were significant (P < 0.0001) in discriminating patients with myelofibrosis from normal individuals with sensitivities 74.14%, 87.93%, 74.14%, and specificities 91.07%, 83.93%, 91.07%, respectively. WIN, WOUT, CE(max) , and WTSP parameters were higher in Group A than in Group B (P < 0.05). Group B exhibited no differences in perfusion parameters as compared with Group C with the exception of WOUT.

CONCLUSION

Patients with myelofibrosis exhibited increased perfusion parameters in vertebral bone marrow, which could be consisted with increased vascularity, probably related to neoangiogenesis as opposed to ET or PV patients showing no increased perfusion. DCE-MRI may be of value in discriminating subgroups of Ph(neg) MPN patients and in indicating those progressing to myelofibrosis.

Correlation of immunohistologic and perfusion vascular parameters with MR contrast enhancement using image-guided biopsy specimens in gliomas

RATIONALE AND OBJECTIVES

The purpose of this study was to correlate the status of magnetic resonance contrast enhancement with immunohistologic vascular parameters such as microvascular cellular proliferation (MVCP), microvascular density (MVD), vascular endothelial growth factor receptor-2 (VEGFR-2) expression, and World Health Organization (WHO) grade obtained from image-guided biopsy specimens. We also compared perfusion computed tomography (PCT) parameters such as cerebral blood volume (CBV), cerebral blood flow (CBF), and permeability surface area-product (PS) with the presence or absence of contrast enhancement.

MATERIALS AND METHODS

A total of 26 image-guided biopsy specimens in 16 patients with treatment naive gliomas were obtained from contrast-enhancing (CE) and nonenhancing (NE) regions of the glioma. Contrast enhancement status was correlated with MVD, MVCP, VEGFR-2 expression, and WHO grade obtained from the biopsy specimen as well as with the PCT parameters.

RESULTS

Contrast enhancement showed statistically significant correlation with MVCP (P = .003) and PS (P = .007) when compared with various immunohistologic and perfusion vascular parameters. WHO grade of the biopsy specimen showed statistically significant correlation with contrast enhancement (P = .002), MVCP (P < .001), and PS values (P = .028).

CONCLUSION

Contrast enhancement in gliomas is primarily from a break in blood-brain barrier as evidenced by its correlation with PS and MVCP, whereas it was not statistically correlated with CBV and MVD even though it showed a positive trend. Contrast enhancement also showed significant correlation with WHO grade suggesting a biopsy from CE region in a heterogeneous glioma probably will still yield the most aggressive part of the glioma is also shown by its association with MVCP and PS estimates.

Modulation of growth and angiogenic potential of oral squamous carcinoma cells in vitro using salvianolic acid B

Background

Our previous studies showed that Salvianolic acid B (Sal B) inhibited 7,12-dimethylbenz[a]anthracene (DMBA)-induced oral carcinogenesis in hamsters and such anti-cancer effects might be related to the inhibition of angiogenesis. This study was aimed to further investigate the anti-proliferative effect of Sal B on the most common type of oral cancer, oral squamous cell carcinoma (OSCC) and the possible mechanisms of action with respect to angiogenesis inhibition.

Methods

Two well-characterized oral squamous cell carcinoma cell lines, CAL27 and SCC4, and premalignant leukoplakia cells were treated with different concentrations of Sal B. Cytotoxicity was assessed by MTT assay. cDNA microarray was utilized to evaluate the expression of 96 genes known to be involved in modulating the biological processes of angiogenesis. Real-time reverse transcription-polymerase chain reaction analysis was conducted to confirm the cDNA microarray data.

Results

Sal B induced growth inhibition in OSCC cell lines but had limited effects on premalignant cells. A total of 17 genes showed a greater than 3-fold change when comparing Sal B treated OSCC cells to the control. Among these genes, HIF-1α, TNFα and MMP9 are specifically inhibited, expression of THBS2 was up-regulated.

Conclusions

Sal B has inhibitory effect on OSCC cell growth. The antitumor effect can be attributed to anti-angiogenic potential induced by a decreased expression of some key regulator genes of angiogenesis. Sal B may be a promising modality for treating oral squamous cell carcinoma.

Combination therapy of transcatheter arterial chemoembolization and arterial administration of antiangiogenesis on VX2 liver tumor

PURPOSE

This study was designed to evaluate the antitumorigenic efficiency of Endostar (an antiangiogenic agent) arterially administrated combined with transcatheter arterial chemoembolization (TACE) on liver tumor, and validation of perfusion CT for quantitative measurements of the results.

EXPERIMENTAL DESIGN

Thirty rabbits bearing VX2 liver tumors were randomly and equally distributed into three groups. One of the following treatment protocols was performed in each group: 1) group 1 was treated with TACE and simultaneously arterially administrated Endostar; 2) group 2 with TACE alone, and 3) a control group that had saline injected through hepatic artery. Routine CT scan was performed before treatment, and perfusion CT imaging was performed 2 weeks after treatment. Immunohistochemical biomarkers of microvascular density (MVD) and the expression of vascular endothelial growth factor (VEGF) were measured for assessments of angiogenesis.

RESULTS

We observed a statistically significant reduction from the control in the volume, growth rate, and size of the tumor 2 weeks after treatment with both TACE plus Endostar and with TACE alone (P < 0.01). Although there was no statistically significant difference in tumor size between the group with TACE plus Endostar and the group with TACE alone (P > 0.05), MVD and VEGF were significantly less expressed in the TACE plus Endostar group than both groups with TACE alone and the control group (P < 0.01). Blood flow (BF), blood volume (BV), and permeability-surface area products (PS) in the group with TACE plus Endostar on perfusion CT were significantly higher than other two groups (P < 0.05), which were positively correlated with the MVD and VEGF values (P < 0.05).

CONCLUSIONS

TACE with arterial administration of Endostar simultaneously significantly inhibited the angiogenesis biomarkers associated with TACE in a rabbit model bearing VX2 liver tumor, which indicates that the combined treatment protocol may have potential synergistic effects on liver cancer. It also is suggested that perfusion CT may be useful for monitoring antiangiogenic/antivascular treatment in the liver tumors.

In vivo correlation of tumor blood volume and permeability with histologic and molecular angiogenic markers in gliomas

BACKGROUND AND PURPOSE

Tumor angiogenesis is very heterogeneous and in vivo correlation of perfusion imaging parameters with angiogenic markers can help in better understanding the role of perfusion imaging as an imaging biomarker. The purpose of this study was to correlate PCT parameters such as CBV and PS with histologic and molecular angiogenic markers in gliomas.

MATERIALS AND METHODS

Thirty-six image-guided biopsy specimens in 23 patients with treatment-naive gliomas underwent PCT examinations. We correlated MVD, MVCP, VEGFR-2 expression, tumor cellularity, and WHO grade of the image-guided biopsy specimens with the PCT parameters. Histologic sections were stained with hematoxylin-eosin, CD34, and VEGFR-2 and examined under a light microscope. These histologic and molecular angiogenic markers were correlated with perfusion parameters of the region of interest corresponding to the biopsy specimen. Pearson correlation coefficients and multiple regression analyses by using clustering methods were performed to assess these correlations.

RESULTS

CBV showed a significant positive correlation with MVD (r = 0.596, P < .001), whereas PS showed a significant positive correlation with MVCP (r = 0.546, P = .001). Both CBV (r = 0.373, P = .031) and PS (r = 0.452, P = .039) also showed a significant correlation with WHO grade. VEGFR-2 positive specimens showed higher PS and CBV; however, neither was statistically significant at the .05 level.

CONCLUSIONS

CBV showed a significant positive correlation with MVD, whereas PS showed a significant positive correlation with MVCP, suggesting that these 2 perfusion parameters represent different aspects of tumor vessels; hence, in vivo evaluation of these could be important in a better understanding of tumor angiogenesis.

The role of perfusion CT as a follow-up modality after transcatheter arterial chemoembolization: an experimental study in a rabbit model

OBJECTIVES

To prospectively evaluate the feasibility of perfusion CT as a follow-up modality after transcatheter arterial chemoembolization (TACE) and to compare these findings with those of histopathology as the reference standard in a VX2 tumor rabbit model.

MATERIALS AND METHODS

VX2 carcinoma tumors were implanted into the liver of 20 rabbits 3 weeks prior to TACE. Perfusion CT was performed prior to TACE and 1- and 4-week after TACE. After obtaining perfusion index maps on perfusion CT, 2 radiologists measured the parametric perfusion indices of blood flow (BF), blood volume (BV), mean transit time (MTT), permeability of the capillary vessel surface (PS), and hepatic arterial fraction (HAF) of primary tumors on pre-TACE perfusion CT, chemoembolized primary tumors on 1-week perfusion CT, and recurred tumors on 4-week perfusion CT. The normal liver parenchyma indices were also recorded. In addition, the radiologists investigated the presence of a recurred tumor adjacent to the chemoembolized area on perfusion index maps of 4-week CT images. The areas of higher hepatic blood flow (HBF), hepatic blood volume (HBV), PS, and HAF, and lower MTT on 4-week perfusion CT than the normal liver parenchyma and the identical area on 1-week perfusion CT were considered as recurred tumors. Histopathology revealed the presence of a recurred tumor, and mean vessel density (MVD) was determined by immunochemical staining for CD31. CT perfusion indices were compared by use of the t test. Comparisons were made for the primary tumor versus normal liver parenchyma on pre-TACE CT, the primary tumor on pre-TACE CT versus the chemoembolized tumor on 1-week CT, the recurred tumor on 4-week CT versus the identical area on 1-week CT, and the primary tumor on pre-TACE CT versus the recurred tumor on 4-week CT. For the detection of recurred tumors, the sensitivity and specificity for 4-week perfusion CT were calculated. Correlation analysis between the recurred tumor perfusion indices and the MVD of the corresponding tumor region was performed. Among 20 rabbits, 6 were excluded from the analysis, and results were based on 14 rabbits.

RESULTS

Recurred tumors were histologically proven in 8 of 14 rabbits (57.1%). The BF, BV, PS, and HAF indices of primary tumors were significantly higher, whereas the MTT was significantly lower than that of the normal liver parenchyma on pre-TACE perfusion CT and that of chemoembolized areas on 1-week perfusion CT (P < 0.05). In addition, recurred tumors also showed significantly higher BF, BV, PS, and HAF, and lower MTT indices than the identical areas on 1-week perfusion CT (P < 0.05). The perfusion indices of recurred tumors were not significantly different from the indices of primary tumors (P > 0.05). Both sensitivity and specificity were 100% for 4-week perfusion CT. There were significant positive correlations between BF (r = 0.947), BV (r = 0.758), PS (r = 0.759), HAF (r = 0.955), and MVD in recurred tumors, and a significant inverse correlation between MTT (r = -0.782) and MVD was observed (P < 0.05).

CONCLUSIONS

We believe that perfusion CT is a feasible alternative modality for the successful early response assessment and early detection of a marginally recurred tumor after TACE. However, perfusion CT has limitations for the prediction of tumor recurrence after TACE.

Vasculogenic mimicry contributes to lymph node metastasis of laryngeal squamous cell carcinoma

Background

Survival of laryngeal squamous cell carcinoma (LSCC) patients has remained unchanged over recent years due to its uncontrolled recurrence and local lymph node metastasis. Vasculogenic mimicry (VM) is an alternative type of blood supplement related to more aggressive tumor biology and increased tumor-related mortality. This study aimed to investigate the unique role of VM in the progression of LSCC.

Methods

We reviewed clinical pathological data of 203 cases of LSCC both prospectively and retrospectively. VM and endothelium-dependent vessel (EDV) were detected by immunohistochemistry and double staining to compare their different clinical pathological significance in LSCC. Survival analyses were performed to assess their prognostic significance as well.

Results

Both VM and EDV existed in LSCC type of blood supply. VM is related to pTNM stage, lymph node metastasis and pathology grade. In contrust, EDV related to location, pTNM stage, T stage and distant metastasis. Univariate analysis showed VM, pTNM stage, T classification, nodal status, histopathological grade, tumor size, and radiotherapy to be related to overall survival (OS). While, VM, location, tumor size and radiotherapy were found to relate to disease free survival (DFS). Multivariate analysis indicated that VM, but not EDV, was an adverse predictor for both OS and DFS.

Conclusions

VM existed in LSCC. It contributed to the progression of LSCC by promoting lymph node metastasis. It is an independent predictors of a poor prognosis of LSCC.

Association of macrophages with angiogenesis in oral verrucous and squamous cell carcinomas

BACKGROUND

Tumor-associated macrophages (TAMs) are a major cellular component of human cancers, yet there is still no consensus as to their role in cancer growth and angiogenesis.

METHODS

The association between TAMs and angiogenesis was investigated in formalin-fixed, paraffin-embedded archival material of oral squamous cell carcinoma (OSCC) and oral verrucous carcinoma (OVC). TAMs shown by immunohistochemistry for CD68 and microvessels demonstrated by immunohistochemistry for CD31 were quantified using an image analyzer computer system.

RESULTS

TAMs were observed in all studied specimens. The area percentage of CD68 immunoreactivity and microvessel density (MVD) were significantly lower in OVC compared with the different grades of OSCC (P = 0.0009), (P = 0.0045). Both parameters increased in high-grade malignancy of OSCC. Linear regression analysis revealed a positive correlation between the area percentage of CD68 immunoreactivity and the MVD in the studied tumors.

CONCLUSIONS

Increased TAMs is associated with angiogenesis and higher histopathological grades in oral cancer.

Immunohistochemistry in the evaluation of neovascularization in tumor xenografts

Angiogenesis, or neovascularization, is known to play an important role in the neoplastic progression leading to metastasis. CD31 or Factor VIII-related antigen (F VIII RAg) immunohistochemistry is widely used in experimental studies for quantifying tumor neovascularization in immunocompromised animal models implanted with transformed human cell lines. Quantification, however, can be affected by variations in the methodology used to measure vascularization including antibody selection, antigen retrieval (AR) pretreatment, and evaluation techniques. To examine this further, we investigated the microvessel density (MVD) and the intensity of microvascular staining among five different human tumor xenografts and a mouse syngeneic tumor using anti-CD31 and F VIII RAg immunohistochemical staining. Different AR methods also were evaluated. Maximal retrieval of CD31 was achieved using 0.5 M Tris (pH 10) buffer, while maximum retrieval of F VIII RAg was achieved using 0.05% pepsin treatment of tissue sections. For each optimized retrieval condition, anti-CD31 highlighted small vessels better than F VIII RAg. Furthermore, the MVD of CD31 was significantly greater than that of F VIII RAg decorated vessels (p<0.001). The choice of antibody and AR method has a significant affect on immunohistochemical findings when studying angiogenesis. One also must use caution when comparing studies in the literature that use different techniques and reagents.

[The effect of the microenvironment of head and neck cancers on tumor progression]

In the last 20 years the incidence and mortality of head and neck squamous cell carcinomas showed an increasing rate in Hungary. In our work we examined the microenvironment of head and neck cancers localized in different anatomical regions. Clinical evidence shows that the prognosis of hypopharyngeal tumors is poorer than that of head and neck cancers in other anatomical locations. We investigated if tumor size or vascularity correlates with the biological behavior of these tumors. The results showed that the tumor size of laryngeal cancers in T2 stage were significantly larger than that of hypopharyngeal cancers in T4 stage. Regarding the vascularity or VEGF expression we did not find any difference between these two tumor types, suggesting that the more aggressive behavior of hypopharyngeal cancers is probably due to the invasive phenotype of this tumor, an assumption supported by genomic examination. In a prospective study we examined the relation between the microvascular density and treatment outcome in irradiated head and neck cancer patients. We demonstrated that the decreased vascularity induced by radiotherapy is a predictive marker of treatment success. We have investigated the role of the endocrine environment in tumor progression, determining the hormone receptor status of head and neck cancers using immunohistochemical and molecular methods. Results showed that ER and PGR are expressed in almost half of the examined tumors, and the presence of functional ER was also frequent in these cases (40.3%), while the solitary hormone receptor expression was a rare phenomenon. Expression of hormone receptors in all the examined cases did not show any correlation with patient survival but in the laryngeal/hypopharyngeal group ER positivity was associated with a shortened survival (p=0.0636). In a multicenter phase I/II clinical trial we examined the tumoral and stromal effects of a natural leukocyte interleukin (LI) in oral squamous cell cancers. LI was administered locally in four different doses. The proportion of tumor cell nests and tumor stroma decreased significantly after LI treatment (induction of fibrosis), which was associated with the induction of necrosis. Morphometric determination of Ki-67+ cells showed a tendency of cycling stromal cells to decrease in response to treatment by the different doses of LI, while lower doses of LI produced a temporary increase in cycling tumor cells. Density of intraepithelial neutrophils was higher after LI treatment, and the stromal density of neutrophils was higher in the responder subgroup. In the tumor stroma macrophage density was similar in the treated and control cases, while a significant decrease of these cells was observed intraepithelially. Finally, we were not able to detect CD34+ immunosuppressive mononuclear cells in these tumors. Our examinations supported the theory that the tumor stroma and its components play an important role in tumor progression, and therapeutic modulation of these components can influence the progression.

The antiangiogenic effect of thalidomide on occult liver metastases: an in vivo study in mice

AIM

To investigate the morphological changes of intratumoral microvessels after administration of thalidomide in occult hepatic metastases.

METHODS

Twenty mice with hepatic metastases created by injection of colon-26 tumor cells into the spleen were enrolled. Ten mice were treated with thalidomide (200 mg/kg) by intraperitoneal injection daily from the first day after inoculation of tumor cells, and the other 10 with saline only. Fifteen days after tumor cell inoculation, the intratumoral microvessels of hepatic metastases in both groups were studied by intravital microscopy and immunohistochemistry.

RESULTS

For the control group, although the intratumoral microvessel density (MVD) and CD34 positive microvessel density (MVD-CD34) of larger metastases (> 400 microm in diameter) were more than those of small metastases respectively (P < 0.01), the intratumoral branch density (BD) was similar to that of small metastases (P > 0.05). For the thalidomide treated group, despite the fact that MVD-CD34 of larger metastases was more than that of small metastases (P < 0.01), the MVD and BD were similar to those of small metastases respectively (P > 0.05). The MVD, BD and MVD-CD34 of small metastases of both groups were similar (P > 0.05); however, those of large metastases in the thalidomide treated group were significantly lower than those in the control group (P < 0.01).

CONCLUSIONS

Thalidomide exerts an antiangiogenic effect on occult hepatic metastases with angiogenesis only, and the different vascular components in the tumor vasculature demonstrate various responses to antiangiogenic therapy.

The lack of correlation between mast cells and microvessel density with pathologic feature of renal cell carcinoma

OBJECTIVE

The growth of solid tumors requires angiogenesis. Evidence indicates that mast cells (MCs) play an important role in tumor angiogenesis but results are not definitive. The aim of this study is to investigate the possible effects of angiogenesis and the presence of MCs on the prognosis of renal cell carcinoma (RCC).

PATIENTS AND METHODS

The study involved 40 patients with RCC (24 men and 16 women who were treated with radical nephrectomy between 1995 and 2006, at our institution. The routine mast cell tryptase staining method was used to assess the MCs in both normal tissue and tumoral tissue. The immunohistochemical staining for CD34 antigen was used for determination of microvessel density. The relation between MC count and tumor status such as tumor stage, size, grade, and other clinicopathologic parameters in RCC were evaluated in this study.

RESULTS

We found no relationship between the number of MCs and patient age, sex, tumor stage, grade, size. No association was noted between angiogenesis and either patient sex or age, tumor size, stage, and grade. No statistically significant correlation was found between the number of MCs and microvessel density in RCC (P-value = 0.45) but the max value of MCs and MVD were in clear cell carcinoma.

CONCLUSIONS

The MC count was not associated with tumor status such as tumor stage, size, grade, and other clinicopathologic parameters, however, MCs may be related to tumor angiogenesis and acceleration of tumor growth in RCC and therefore need further evaluation in RCC.

Heterogeneity of tumor prognostic markers: a reproducibility study applied to liver metastases of pancreatic endocrine tumors

Liver biopsy of metastatic pancreatic endocrine tumors allows confirmation of the diagnosis and assessment of prognosis. However, sampling variability is a potential limitation. Our aim was to use the tissue microarray technique to assess the heterogeneity of three prognostic markers, ie, MIB-1 proliferation index, microvascular density and somatostatin receptor type 2, inside single or between synchronous or metachronous liver metastases of pancreatic endocrine tumors. Tissue microarrays were constructed, which included core biopsies taken from surgically resected liver metastases in 29 patients. MIB-1, microvascular density and somatostatin receptor type 2 were evaluated after immunostaining. The heterogeneity was highlighted by the calculation of the reproducibility of the values of two cores randomly selected among all the cores studied. For quantitative variables, it was assessed by the intraclass correlation coefficient and by a Bland-Altman approach. For qualitative variables, observed agreement and weighted kappa were given. A total of 184 liver metastases were analyzed. For MIB-1, the intraclass correlation coefficients were 0.63, 0.69 and 0.67 and for microvascular density, the intraclass correlation coefficients were 0.48, 0.60 and 0.00, respectively, in single, synchronous and metachronous liver metastases. The variability increased for higher mean values of microvascular density. For somatostatin receptor type 2, the observed agreements were 91% (kappa=0.81), 69% (kappa=0.49) and 79% (kappa=0.68) in single, synchronous and metachronous liver metastases, respectively. In conclusion, tissue microarray analysis identifies heterogeneity of protein expression in pancreatic endocrine metastases, which depends on the marker tested. The reproducibility is better for MIB-1 and somatostatin receptor type 2 than for microvascular density. Sampling variability should be taken into consideration as a potential limitation to the assessment of prognostic and therapeutic markers in biopsy samples from metastatic pancreatic endocrine tumors.

Heterogeneity of angiogenesis and blood vessel maturation in cartilage tumors

Cartilage tumors have a special angiogenic phenotype, with blood vessels arranged predominantly in pericartilage fibrous septa and relatively low microvessel density (MVD), except in dedifferentiated chondrosarcomas. To further elucidate angiogenesis in cartilage tumors, we used double-labeling immunohistochemistry to determine microvessel pericyte coverage index (MPI) and proliferating capillary index (PCI), referring to blood vessel maturation and angiogenic activity in enchondromas, conventional chondrosarcomas, and dedifferentiated chondrosarcomas. Altogether, we found high MPIs (>70%) especially in dedifferentiated chondrosarcomas but without a correlation to the grade of malignancy. PCI was significantly higher in conventional chondrosarcomas grades II and III than in enchondromas, chondrosarcomas grade I, and dedifferentiated chondrosarcomas. Thus, PCI positively correlated with the previously reported differential expression of vascular endothelial growth factor (VEGF)-A in cartilage tumors. Altogether, cartilage tumors exhibit a heterogeneous but predominantly mature angiogenic phenotype with differential proliferative activity.

Assessing tumor angiogenesis in histological samples

Tumor neovascularization acquires vessels through a number of processes, including angiogenesis, vasculogenesis, vascular remodelling, intussusception, and possibly vascular mimicry in certain tumors. The end result of the tumor vasculature has been quantified by counting the number of immunohistochemically identified microvessels in areas of maximal vascularity so-called hot spots. Other techniques have been developed, such as Chalkley counting and the use of image analysis systems that are robust and reproducible as well as more objective. Many of the molecular pathways that govern tumor neovascularization have been identified, and many reagents are now available to study these tissue sections. These include angiogenic growth factors and their receptors, cell adhesion molecules, proteases, and markers of activated, proliferating, cytokine-stimulated, or angiogenic vessels, such as CD105. It is also possible to differentiate quiescent from active vessels. Other reagents that can identify proteins involved in microenvironmental influences such as hypoxia have also been generated. Although the histological assessment of tumor vascularity is used mostly in the research context, it may also have clinical applications if appropriate methodology and trained observers perform the studies.

Pancreatic endocrine tumors: tumor blood flow assessed with perfusion CT reflects angiogenesis and correlates with prognostic factors

PURPOSE

To prospectively correlate multidetector computed tomographic (CT) perfusion measurement of pancreatic endocrine tumors with tumor microvascular density (MVD) assessed by using histologic techniques and to determine whether perfusion CT parameters differ between tumor grades.

MATERIALS AND METHODS

Institutional review board approval and informed consent were obtained. Thirty-six patients (15 men, 21 women; mean age, 53 years; range, 18-78 years) with resectable pancreatic endocrine tumors underwent presurgical dynamic perfusion CT. Twenty-eight (78%) of 36 patients were included in the study group; eight were excluded because of artifacts that were not compatible with perfusion postprocessing. Multidetector CT perfusion data were analyzed to calculate tumor and normal pancreatic blood flow, blood volume, mean transit time, and permeability-surface area product. Multidetector CT perfusion parameters were compared with intratumoral MVD by using the Spearman correlation coefficient and with World Health Organization (WHO) classification, tumor size, tumor proliferation index, hormonal profile, and presence of metastases by using Mann-Whitney tests.

RESULTS

High correlation (r = 0.620, P < .001) was observed between tumor blood flow and intratumoral MVD. Blood flow was significantly higher (P = .02) in the group of benign tumors (WHO 1) than in the groups of tumors of indeterminate prognosis (WHO 2) or well-differentiated carcinomas (WHO 3). Blood flow was significantly higher in tumors with a proliferation index of 2% or less (P = .005) and in those without histologic signs of microscopic vascular involvement (P = .008). Mean transit time was longer in tumors with lymph node (P = .02) or liver (P = .05) metastasis.

CONCLUSION

Perfusion CT is feasible in patients with pancreatic endocrine tumors and reflects MVD. Perfusion CT measurements are correlated with histoprognostic factors, such as proliferation index and WHO classification.

Imaging hemodynamics

Microvascular permeability is a pharmacologic indicator of tumor response to therapy, and it is expected that this biomarker will evolve into a clinical surrogate endpoint and be integrated into protocols for determining patient response to antiangiogenic or antivascular therapies. This review discusses the physiological context of vessel permeability in an imaging setting, how it is affected by active and passive transport mechanisms, and how it is described mathematically for both theoretical and complex dynamic microvessel membranes. Many research groups have established dynamic-enhanced imaging protocols for estimating this important parameter. This review discusses those imaging modalities, the advantages and disadvantages of each, and how they compare in terms of their ability to deliver information about therapy-associated changes in microvessel permeability in humans. Finally, this review discusses future directions and improvements needed in these areas.

Morphologic changes of mammary carcinomas in mice over time as monitored by flat-panel detector volume computed tomography

Noninvasive methods are strongly needed to detect and quantify not only tumor growth in murine tumor models but also the development of vascularization and necrosis within tumors. This study investigates the use of a new imaging technique, flat-panel detector volume computed tomography (fpVCT), to monitor in vivo tumor progression and structural changes within tumors of two murine carcinoma models. After tumor cell inoculation, single fpVCT scans of the entire mice were performed at different time points. The acquired isotropic, high-resolution volume data sets enable an accurate real-time assessment and precise measurements of tumor volumes. Spreading of contrast agent-containing blood vessels around and within the tumors was clearly visible over time. Furthermore, fpVCT permits the identification of differences in the uptake of contrast media within tumors, thus delineating necrosis, tumor tissues, and blood vessels. Classification of tumor tissues based on the decomposition of the underlying mixture distribution of tissue-related Hounsfield units allowed the quantitative acquisition of necrotic tissues at each time point. Morphologic alterations of the tumor depicted by fpVCT were confirmed by histopathologic examination. Concluding, our data show that fpVCT may be highly suitable for the noninvasive evaluation of tumor responses to anticancer therapies during the course of the disease.

Relationship between retention of a vascular endothelial growth factor receptor 2 (VEGFR2)-targeted ultrasonographic contrast agent and the level of VEGFR2 expression in an in vivo breast cancer model

OBJECTIVE

The aim of this study was to characterize the relationship between retention of a vascular endothelial growth factor receptor 2 (VEGFR2)-targeted ultrasonographic contrast agent (UCA) and VEGFR2 expression in tumor vasculature of breast cancer.

METHODS

67NR breast cancer tumors implanted in mice were evaluated in vivo with both VEGFR2-targeted and nontargeted UCAs, and a high-frequency ultrasound system. A bolus of the UCA was injected and allowed to circulate for 4 minutes to allow binding of targeted microbubbles. After that, 2 sets of images before and after a high-power ultrasonic destruction sequence were acquired. The average video intensity of predestruction and postdestruction images was measured and used as a relative measure of retention of the UCA in the tumor. Levels of VEGFR2 expression and tumor vascular density were quantified by immunohistochemical staining and compared with retention of the VEGFR2-targeted UCA.

RESULTS

Retention of VEGFR2-targeted microbubbles in tumors was significantly higher than retention of nontargeted microbubbles (mean +/- SD, 47.75+/-9.85 versus 18.5+/-5.46 dB; P< .001). Retention of the VEGFR2-targeted UCA was found to correlate with the level of VEGFR2 expression in the studied tumors (r(2)=0.41). In contrast, retention of the nontargeted UCA was not correlated with the level of VEGFR2 expression (r(2)=0.08). Furthermore, retention of the VEGFR2-targeted UCA was not correlated with the level of tumor vascularity.

CONCLUSIONS

The magnitude of the molecular ultrasonographic signal from a VEGFR2-targeted UCA retained by tissue correlates with VEGFR2 expression. These results validate the use of molecular ultrasonography for in vivo detection and quantification of VEGFR2 expression in this breast cancer model.

Comparison of tumor histology to dynamic contrast enhanced magnetic resonance imaging-based physiological estimates

PURPOSE

The purpose of this study was to compare histologically determined cellularity and extracellular space to dynamic contrast-enhanced magnetic resonance imaging (DCE MRI)-based maps of a two-compartment model's parameters describing tumor contrast agent extravasation, specifically tumor extravascular extracellular space (EES) volume fraction (ve), tumor plasma volume fraction (vp) and volume-normalized contrast agent transfer rate between tumor plasma and interstitium (KTRANS/VT).

MATERIALS AND METHODS

Obtained ve, vp and KTRANS/VT maps were estimated from gadolinium diethylenetriamine penta-acetic acid DCE T1-weighted gradient-echo images at resolutions of 469, 938 and 2500 microm. These parameter maps were compared at each resolution to histologically determined tumor type, and the high-resolution 469-microm maps were compared with automated cell counting using Otsu's method and a color-thresholding method for estimated intracellular (Vintracellular) and extracellular (Vextracellular) space fractions.

RESULTS

The top five KTRANS/VT values obtained from each tumor at 469 and 938 microm resolutions are significantly different from those obtained at 2500 microm (P<.0001) and from one another (P=.0014). Using these top five KTRANS/VT values and the corresponding tumor EES volume fractions ve, we can statistically differentiate invasive ductal carcinomas from noninvasive papillary carcinomas for the 469- and 938-microm resolutions (P=.0017 and P=.0047, respectively), but not for the 2500-microm resolution (P=.9008). The color-thresholding method demonstrated that ve measured by DCE MRI is statistically similar to histologically determined EES. The Vextracellular obtained from the color-thresholding method was statistically similar to the ve measured with DCE MRI for the top 10 KTRANS/VT values (P>.05). DCE MRI-based KTRANS/VT estimates are not statistically correlated with histologically determined cellularity.

CONCLUSION

DCE MRI estimates of tumor physiology are a limited representation of tumor histological features. Extracellular spaces measured by both DCE MRI and microscopic analysis are statistically similar. Tumor typing by DCE MRI is spatial resolution dependent, as lower resolutions average out contributions to voxel-based estimates of KTRANS/VT. Thus, an appropriate resolution window is essential for DCE MRI tumor diagnosis. Within this resolution window, the top KTRANS/VT values with corresponding ve are diagnostic for the tumor types analyzed in this study.

Dynamic contrast-enhanced MRI of benign prostatic hyperplasia and prostatic carcinoma: correlation with angiogenesis

AIM

To investigate the diagnostic and differential diagnostic values of dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) in prostatic diseases, and to investigate the correlation between the parameters of SI-T curves and angiogenesis.

MATERIALS AND METHODS

Twenty-one patients with proven prostatic carcinoma (Pca) and 29 patients with proven benign prostatic hyperplasia (BPH) were examined using DCE MRI. Diagnostic characteristics for differentiation were examined using threshold values for maximum peak time, enhancement degree, and enhancement rate. Then, the signal intensity-time curves (SI-T curves) were analysed, and the correlations between the parameters of SI-T curves and the expression levels of vascular endothelial growth factor (VEGF) and microvascular density (MVD) were investigated. All patents underwent prostatectomy. DCE MRI and histological findings were correlated.

RESULTS

Pca showed stronger enhancement with an earlier peak time, higher enhancement, and enhancement rate (p<0.05). Regarding the type of SI-T curves, in the BPH group six were type A, 10 were type B, and 13 were type C, whereas in the Pca group, 14 were type A, six were type B, and only one was type C (Chi-square test, chi2=13.57, P<0.005). The VEGF and MVD expression levels of Pca were higher than those of BPH. Peak time was negatively correlated with the expression levels of VEGF and MVD, whereas the enhancement degree and enhancement rate showed positive correlations (Pearson correlation, p<0.05).

CONCLUSION

Based on T2-weighted imaging, DCE MRI curves can help to differentiate benign from malignant prostate tissue. In the present study the type C curve was rarely seen with malignant disease, but these results need confirmation.

A non-invasive, in vivo technique for monitoring vascular status of glioblastoma during angiogenesis

The growth of solid tumors dependent on the process of angiogenesis in which growth factors secreted by tumor and stromal cells promote endothelial cell proliferation, migration, and maturation. This process generates a tumor-specific vascular supply and enables small or dormant tumors to grow rapidly with exponential increases in tumor volume. Determination of tumor oxygenation at the microvascular level will provide important insight into tumor growth, angiogenesis, necrosis, and therapeutic response, and will facilitate to develop protocols for studying tumor behavior. A non-invasive multi-modality approach based on near infrared spectroscopy (NIRS) technique, namely: Steady State Diffuse Optical Spectroscopy (SSDOS) along with Magnetic Resonance Imaging (MRI) is applied for monitoring the concentration of oxyhemoglobin, deoxyhemoglobin and water within tumor region and for studying the vascular status of tumor and the patho-physiological changes that occur during angiogenesis. Since, the growth of solid tumors depends on the formation of new blood vessels, an association between intramural microvessel density (MVD) and tumor oxygenation is also investigated. The relative decrease in oxygenation value with tumor growth indicates that though blood vessels infiltrate and proliferate the tumor region, a hypoxic trend is clearly present.

Expression of vascular endothelial growth factor and assessment of microvascular density with CD 34 and endoglin in proliferative endometrium, endometrial hyperplasia, and endometrial carcinoma

The aim of this study was to compare vascular endothelial growth factor (VEGF), CD 34, and endoglin expressions as markers of angiogenesis in proliferative endometrium (PE), endometrial hyperplasia (EH), and endometrial carcinoma (EC) and to find the possible impact of angiogenesis on malign transformation. Formalin-fixed, paraffin-embedded tissues from 12 patients with PE, 23 patients with simple EH and complex EH with atypia, and 31 patients with EC were included. A semiquantitative scoring system was used to assess the intensity and degree of staining of VEGF. Microvessel density (MVD) was assessed with endoglin and anti-CD 34 in most vascular areas. VEGF expression was significantly higher in EC and EH than PE, but there was no difference between EC and EH. According to CD 34 staining, there were no differences in MVD between groups. However, mean MVD counts assessed by endoglin were significantly higher in EC than PE and EH. Although VEGF expression in EC was significantly higher, it did not correlate with other measures of angiogenesis. MVD using endoglin seemed to reflect neoplastic angiogenesis better than CD 34

A noninvasive multimodal technique to monitor brain tumor vascularization

Determination of tumor oxygenation at the microvascular level will provide important insight into tumor growth, angiogenesis, necrosis and therapeutic response and will facilitate to develop protocols for studying tumor behavior. The non-ionizing near infrared spectroscopy (NIRS) technique has the potential to differentiate lesion and hemoglobin dynamics; however, it has a limited spatial resolution. On the other hand, magnetic resonance imaging (MRI) has achieved high spatial resolution with excellent tissue discrimination but is more susceptible to limited ability to monitor the hemoglobin dynamics. In the present work, the vascular status and the pathophysiological changes that occur during tumor vascularization are studied in an orthotopic brain tumor model. A noninvasive multimodal approach based on the NIRS technique, namely steady state diffuse optical spectroscopy (SSDOS) along with MRI, is applied for monitoring the concentrations of oxyhemoglobin, deoxyhemoglobin and water within tumor region. The concentrations of oxyhemoglobin, deoxyhemoglobin and water within tumor vasculature are extracted at 15 discrete wavelengths in a spectral window of 675-780 nm. We found a direct correlation between tumor size, intratumoral microvessel density and tumor oxygenation. The relative decrease in tumor oxygenation with growth indicates that though blood vessels infiltrate and proliferate the tumor region, a hypoxic trend is clearly present.

Use of an artificial lymphatic system during carboplatin infusion to improve canine osteosarcoma blood flow and clinical response

BACKGROUND

The artificial lymphatic system (ALS), a mechanical system designed to reduce increased interstitial fluid pressure in solid tumors and enhance the delivery of chemotherapy, was evaluated within a randomized clinical trial treating spontaneously occurring canine appendicular osteosarcoma (OS), a tumor similar to its human OS counterpart.

METHODS

An ALS was investigated for its ability to increase OS blood flow and increase uptake of intravenously administered carboplatin.

RESULTS

Blood flow increased by 314% in tumors with active ALS drains versus 126% in control tumors (P < .03). Tumor carboplatin uptake increased by 51% after drain activation (P = .07). Microvascular density (MVD) was measured in tumors after surgical amputation and in corresponding bone regions in a cohort of normal dogs. The OS tumors had equivalent MVD as normal bone, and MVD was higher in the humerus than the femur (P < .03) in both tumor and normal bone. Median survival between the ALS-treated and control cohorts was not different despite increased drug uptake or ALS manipulation. Compared with historic controls, ALS drain insertion into tumors to reduce interstitial fluid pressure did not worsen the prognosis.

CONCLUSIONS

The findings in canine spontaneously occurring OS indicate that an ALS may be of value as a chemotherapy adjunct for enhancing the delivery of chemotherapy to tumor interstitium.